Remove the salmon from the refrigerator and let it sit for 15–30 minutes to reach room temperature. Cut the fish into four equal portions, then pat each piece dry with paper towels. Generously season both sides with garlic powder, salt, and pepper.

In a large skillet, heat a mix of butter and olive oil over medium-high heat until sizzling, about 1-2 minutes. Carefully add the salmon portions; sear them for 3-4 minutes until they develop a rich golden-brown crust. Flip the salmon and cook for an additional 3-4 minutes, then transfer it to a plate while it’s still slightly undercooked in the center.

In the same skillet, add chopped onions, stirring them into the remaining butter and oil. Sauté on medium heat for about 5 minutes until the onions become softened and lightly golden.

Pour in the chicken broth and freshly squeezed lemon juice, scraping up any browned bits from the bottom of the skillet. Stir in the Boursin cheese, mixing until smooth and creamy. Allow the sauce to gently bubble for 4-5 minutes.

Reduce the heat to low and return the seared salmon to the skillet, ensuring it is immersed in the sauce. Cook for an additional 3-5 minutes, monitoring closely until the salmon is fully cooked and flakes easily with a fork.

Taste the creamy sauce and adjust the seasoning as needed with additional salt and pepper. Plate the Boursin salmon and spoon the rich sauce generously over the top. Serve immediately, garnished with fresh parsley.